"Cubby" wrote:

I need to raise up the roof of a porch a bit to get old columns out and new
ones in. I was hoping to use the type of jacks I see (and used ages ago)
on concrete pours to plumb up the forms. Basically was thinking of
attaching a 4x4 to each end of the jack and then be able to turn the
turnscrew in the center to raise and lower the roof. First question:
What are these called? 2nd: Can I do this or am I asking for trouble?
Next, if these are not recommended for use, then I suspect I'll be heading
the bottle jack route which is fine but I'll
have to do each one individually as I don't have 4 bottle jacks (number of
colums to be removed). Thanks for any inputs.

Lally Column?

http://www.hammerzone.com/archives/f...t1/raising.htm